Flanges

First Distributors offers a wide range of flanges and can typically provide the following for same-day or next-day delivery. Large quantites, custom sizes, and special alloys (Alloy 20, Monel, Hastelloy, Inconel, Titanium, etc) may be subject to a longer lead time for delivery.

Items Typically on the shelf:




	Size Range: 1/2" - 48" Diameter


	Types: Slip On, Socket Weld, Weld Neck, Threaded, Blind, Lap Joint, Long Weld Neck, Orifice/Orifice Plate, and API Flange


	Class: 150 through 2500


	Carbon Steel: A105


	Stainless Steel: 304, 316

Those Potentially Requiring A Lead Time:




	Carbon Steel: A350, A694


	Stainless Steel: 310, 321, 347


	Exotic Alloys: A20, C276, Duplex 2205, Duplex 2507, AL6XN, A200, A600, Monel, Inconel, Incoloy 800, Incoloy 825, Aluminum, Titanium

A Guide To Flange Materials

Carbon & Stainless Flanges

Standard Carbon Steel Flanges (A105): ASTM A105 is an ASTM specification dealing with forged carbon steel piping components
Stainless Steel Flanges (A182): This specification covers forged or rolled alloy and stainless steel (304, 304L, 316L) flanges. This spec also covers other alloys including chrome (i.e. A182 F11)
High Yield Flanges (F694): ASTM A694 is the standard specification to cover carbon and alloy steel forgings for pipe flanges, fitting, valves and other parts for high-pressure transmission service. Applications include, but are not limited to, in wellhead and Christmas-tree manifold equipment in oil and gas industry. The two numbers in each grade indicate the yield strength requirements, in ksi.
Low-Temp Flanges (A350): This specification covers several grades of carbon and low alloy steel forged or ring-rolled flanges (LF2 in low-temp applications).

Wedge Gate

Alloy 20
Duplex 2205
Super Duplex 2507
Hastelloy C276
Incoloy 800
Incoloy 825
Monel 400
Inconel 625

Connection Types Explained (Type Of Flange)

Weld neck

Circumferentially welded into the system at its neck so that the integrity can be easily examined by radiography.
The bore of the pipe and flange match in order to reduce turbulence and erosion, thus making it the strongest connection type and the most favorable in critical applications.

Slip-on

Slipped over the pipe and the fillet welded. These are easy to use in fabricated applications, fabricated meaning that the pipeline is predesigned for a particular use. Often used instead of a weld neck when cost or space is a major concern.

Threaded

Threaded Flanges are used for special circumstances with their main advantage being that they can be attached to the pipe without welding. Threaded flanges can be removed easily. Sometimes a seal weld is also used in conjunction with the threaded connection.

Blind

Used to “blank off” pipelines, valves, and pumps. Sometimes, you might hear this referred to as an inspection cover, or blanking flange.

Socket weld

Counter-bored to accept the pipe before being fillet welded. Used in 4” and smaller high-pressure systems.
The bore of the pipe and flange match, thus providing good flow characteristics.

Lap joint

Always used with either a stub end or taft which is butt-welded to the pipe with the flange loose behind it. The stub end/taft always makes the face. Used in systems that need frequent cleaning.
Favored in low pressure applications because it is easily assemble and aligned. These flanges look very similar to a slip on, but the are distinguished by the rounded interior edge of the flange face.
To reduce cost these flanges can be supplied without a hub and/or in treated, coated carbon steel

Pressure Class Information

These classes include: 150 LBS, 300 LBS, 400 LBS, 600 LBS, 900 LBS, 1500 LBS, and 2500 LBS.

A higher class rating will increase the weight, height, face, and often times change the stud bolts required for installation. Precise dimensions for each flange, by class, can be viewed in our technical flange specification page.

Bolt chart for flanges by class can be seen here

Face Types Available

Raised Face

The most common face type. The gasket surface is raised above the bolting circle face. Allows for the use of a wide array of gasket designs. Spiral Wound, Cut, etc.
Primary purpose is to concentrate more pressure on a smaller gasket area and thereby increase the pressure containment capability of the joint, creating a more secure connection.

Full face

Gasket surface is on the same plane as the bolting circle face.
Often used in applications where the mating flange or fitting is made from a casting since relatively brittle cast iron requires a full-face contact point.

Ring-type face

Has grooves cut into the face into which the gasket is placed. The flanges seal when tightened bolts compress the gasket into the grooves. This is referred to as “coining” the gasket. Ring type joints excel in high-pressure, high-temperature applications such as oil field drilling equipment. RTJs are also used on valves and pipework assemblies.

Series A Vs Series B

For flanges above 24", the flange must be specified for either series A or series B. These are competing specifications that were brought together in B16.47. ASME has incorporated most of the MSS-SP44 spec into B16.47 Series A and most of the API 605 spec into B16.47 series B. Weld necks and blinds are covered under these two specs. For slip-ons over 24”, you must refer to either Industry Standard or Boiler Code flanges.

Manufacturers Commonly Available

We can provide flanges from a large selection of manufacturers, with several of them listed below.




	Manufacturer Country




	Bebitz Germany


	Buffalo Flange USA


	DL Flange USA


	Galperti Flange USA/Italy


	Goodluck Steel India


	Kerkau USA


	Metalfar Italy


	National Flange USA


	Technoforge Italy


	Trilad USA


	Ulma Spain


	Viraj India


	Weldbend USA